Another tip on tumblr is if you notice that a blog you follow reblogs a lot of stuff from other users, follow those users as well because they are the source of the funny and will probably provide you with even more. (not guaranteed)

It just sets a different tone altogether. There are even a few posts about it on the site called "tumblr grammar". Such as using "omg" and "idk" as commas and periods, wanting to start the sentence with a capital letter but then remembering this is Tumblr, not a commencement address.
One of my favorite posts involves a wordart post that says, "ur beautiful".
Someone responded, "This is sweet except I'd prefer you add a capital Y and an o and an apostrophe e"
So they responded again with word art. "ur beautifulYo'e"